Fix -iframe class for gallery [noelboss#340]

Author: marcandre

src/featherlight.js

@@ -241,13 +241,12 @@
 		/* sets the content of $instance to $content */
 		setContent: function($content){
 			var self = this;
-			/* we need a special class for the iframe */
-			if($content.is('iframe')) {
-				self.$instance.addClass(self.namespace+'-iframe');
-			}
 
 			self.$instance.removeClass(self.namespace+'-loading');
 
+			/* we need a special class for the iframe */
+			self.$instance.toggleClass(self.namespace+'-iframe', $content.is('iframe'));
+
 			/* replace content by appending to existing one before it is removed
 			   this insures that featherlight-inner remain at the same relative
 				 position to any other items added to featherlight-content */